CN115335028A

CN115335028A - Agent for improving oxidative lightening of keratin-containing fibers

Info

Publication number: CN115335028A
Application number: CN202180024899.9A
Authority: CN
Inventors: K·古特西斯; D·凯斯勒-贝克尔
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2020-03-31
Filing date: 2021-01-05
Publication date: 2022-11-11
Also published as: JP2023519415A; EP4125779A1; WO2021197673A1; US20230201089A1; DE102020204145A1

Abstract

The invention relates to a medicament for lightening keratin fibres, in particular human hair, comprising (a) at least one oxidizing agent, (b) at least one complexing agent of general formula (I),

Description

Agent for improving oxidative lightening of keratin-containing fibers

The present invention relates to agents for oxidative coloration in the field of cosmetics, which are particularly suitable for lightening (lightening) keratin fibres, in particular human hair.

Changing hair style and hair color is an important area of modern cosmetics. In addition to coloring, lightening or bleaching hair is a particular desire of many consumers because light color hair color is considered attractive and desirable in fashion. For this purpose, various lightening agents (blobbing agents) having different lightening properties are on the market.

The oxidizing agent contained in the hair dye can lighten the hair fiber by oxidizing the melanin pigment which destroys the hair itself. In order to obtain a moderate lightening effect, it is sufficient to use hydrogen peroxide alone (possibly with the addition of ammonia or other alkalinizing agents) as oxidizing agent; to obtain a stronger lightening effect, mixtures of hydrogen peroxide and peroxodisulfates and/or peroxomonosulfates are generally used.

In the case of dark initial hair, a longer application time and/or repeated lightening processes are often required to lighten the hair through several shades. However, this is also accompanied by greater damage to the hair, since not only the colorants of the hair but also other structural components of the hair are subject to oxidative damage. Depending on the degree of damage, this loss ranges from coarse, fragile hairs that are more difficult to comb through to a reduction in the endurance and tensile strength of the hair to hair breakage.

The use of complexing agents in the oxidative coloration of keratin fibers is well known. Among these, complexing agents are intended to prevent hydrogen from being decomposed by metal ions accumulated in the hair fibers.

For example, EP 1714634A1 describes a hair treatment kit for coloring human hair comprising a first compartment containing a complexing agent and a second compartment containing an agent for coloring. The use of complexing agents is intended to prevent undesirable reactions on or with the hair that lead to undesirable heating.

Many of the light hair coloring products on the market use HEDP (etidronic acid) or its salts or EDTA (ethylenediaminetetraacetic acid) or its salts as complexing agents. Both HEDP and EDTA are effective in stabilizing hydrogen peroxide and in so effectively complexing the metal ions present that undesirable temperature increases during application are almost completely avoided. However, a major disadvantage of HEDP and EDTA is their poor biodegradability. In particular, recently, users are increasingly concerned about the eco-benefit characteristics of cosmetics they use. It is therefore of utmost importance that the user prefers a cosmetic product that is as sustainable as possible and that contains biodegradable components.

It was therefore the object of the present invention to find hair lightening agents with biodegradable complexing agents which are at least comparable to, and preferably even better than, the hair lightening agents or lightening agents known from the prior art with respect to their hair lightening properties. Furthermore, the hair dye should have sufficiently high stability and should not generate excessive heat even when applied to hair having a high metal or heavy metal content. In addition, the use of complexing agents in lightening or hair dye should reduce hair damage.

Surprisingly, it has now been found that this task can be completely solved if a lightening or dye lightening agent is used which, in addition to at least one oxidizing agent (a), also comprises at least one specific complexing agent (b) of the specific formula (I) and a radical scavenger (c).

A first object of the present invention is an agent for lightening keratin fibres, in particular human hair, comprising:

(a) At least one kind of oxidizing agent is added,

(b) At least one complexing agent of the general formula (I),

wherein

R ₁ Represents a hydrogen atom, C ₁ -C ₆ Alkyl, hydroxy-C ₂ -C ₆ Alkyl, carboxy-C ₁ -C ₆ An alkyl group or a physiologically acceptable salt thereof,

R ₂ 、R ₃ independently of each other, a hydrogen atom, C ₁ -C ₆ Alkyl, hydroxy-C ₂ -C ₆ Alkyl, carboxy-C ₁ -C ₆ An alkyl group or a physiologically acceptable salt thereof,

M ₁ 、M ₂ independent of each otherAnd represents a hydrogen atom or an equivalent of an alkali metal, alkaline earth metal or metal ion, preferably sodium, potassium, 1/2 magnesium, 1/2 calcium, 1/2 zinc or ammonium ion (NH) ₄ ⁺ ) And are each selected from

(c) At least one free radical inhibitor.

Keratin fibres

Keratin fibers or keratinous fibers refer to fur, wool, feathers, and in particular human hair. Although the agents are primarily suitable for lightening keratin fibres, there is nothing in principle to prevent their use in other fields.

Agent for lightening keratin fibres

The term "lightening keratin fibres" as used in the present invention includes any form of colour change of the fibres in which the keratin fibres have a lighter colour than that present prior to administration of the medicament. This includes in particular the color changes covered by the terms lightening, lightening and bleaching. Lightening of hair color is caused by the presence of an oxidizing agent in the medicament. In addition to the oxidizing agent, the agent of the present invention may also contain a colorant component for shading purposes, such as an oxidative dye precursor and/or a direct dye. The colorant component can readily alter the color appearance of the final coloration. However, according to the invention, these colorant components are present in the medicament in such small amounts that the color impression of the keratin fibers treated with the medicament is still lighter than their original color. The corresponding coloring technique may be referred to as coloring lightening or fine lightening.

The agents comprise the essential ingredients (a), (b) and (c) of the invention, preferably in a cosmetic carrier. For example, suitable aqueous, alcoholic, or hydro-alcoholic carriers can be used as cosmetic carriers for pharmaceutical agents. For hair colouring purposes, such carriers are, for example, creams, emulsions, gels, pastes or surfactant-containing foaming solutions, such as shampoos, foam aerosols, foam formulations or other formulations suitable for application to the hair.

A first object of the present invention is therefore an agent for lightening keratin fibres, in particular human hair, comprising, in a cosmetic carrier:

(a) At least one kind of oxidizing agent is added,

(b) At least one complexing agent of the general formula (I),

wherein

M ₁ 、M ₂ independently of one another, represents a hydrogen atom, or the equivalent of an alkali metal, alkaline earth metal or metal ion, preferably sodium, potassium, 1/2 magnesium, 1/2 calcium, 1/2 zinc or ammonium ion (NH) ₄ ⁺ ) And are each selected from

(c) At least one free radical inhibitor.

The agent according to the invention is a ready-to-use agent which can be applied in this form to the keratin fibres for the purpose of lightening or lightening.

Oxidant (a)

As a first essential component, the medicament according to the invention comprises at least one oxidizing agent (a). To achieve a moderate lightening effect, hydrogen peroxide is the preferred oxidizing agent. Preferred agents as hair dyes and bleaches are furthermore characterized by comprising hydrogen peroxide and/or one of its solid addition products with organic or inorganic compounds. However, if a stronger lightening or lightening effect is desired, hydrogen peroxide is used with a stronger oxidizing agent such as a persulfate (sodium, potassium or ammonium persulfate).

In the context of a particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises

(a) Comprising at least one oxidizing agent selected from the group consisting of hydrogen peroxide, ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate.

Ammonium peroxodisulfate, which may also be referred to as ammonium persulfate, is understood to mean a compound having the empirical formula (NH) ₄ ) ₂ S ₂ O ₈ Persulfate of (4).

Potassium peroxodisulfate, which may also be called potassium peroxodisulfate, is of the formula K ₂ S ₂ O ₈ Persulfate of (4).

Sodium peroxodisulfate, also called sodium persulfate, is of the formula Na ₂ S ₂ O ₈ Persulfate of (4).

(a1) Hydrogen peroxide and

(a2) At least one persulfate salt selected from the group consisting of ammonium persulfate, potassium persulfate and sodium persulfate.

Accordingly, a first object of the present invention is an agent for lightening keratin fibres, in particular human hair, comprising

(a1) Hydrogen peroxide and

(a2) At least one persulfate salt selected from the group consisting of ammonium persulfate, potassium persulfate and sodium persulfate, and

(b) At least one complexing agent of the general formula (I),

wherein

R ₂ 、R ₃ independently of one another, a hydrogen atom, C ₁ -C ₆ Alkyl, hydroxy-C ₂ -C ₆ Alkyl, carboxy-C ₁ -C ₆ An alkyl group or a physiologically acceptable salt thereof,

M ₁ 、M ₂ independently of one another, represents a hydrogen atom, or the equivalent of an alkali metal, alkaline earth metal or metal ion, preferably sodium, potassium, 1/2 magnesium, 1/2 calcium, 1/2 zinc or ammonium ion (NH) ₄ ⁺ ) And are and

(c) At least one free radical inhibitor.

In a preferred embodiment, the hydrogen peroxide itself is used as an aqueous solution. The concentration of the hydrogen peroxide solution in the medicament according to the invention is determined on the one hand by the regulatory requirements and on the other hand by the desired effect; preferably, 3 to 12% by weight aqueous solutions are used. The preferred pharmaceutical agent according to the invention of the first subject matter of the invention is characterized in that it comprises (a) 0.1 to 12.0 wt. -%, preferably 0.5 to 10.5 wt. -%, further preferably 1.0 to 8.5 wt. -%, still further preferably 1.5 to 7.0 wt. -% and most preferably 1.5 to 6.0 wt. -% of hydrogen peroxide, based on the total weight of the pharmaceutical agent.

In the context of a particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises (a) 0.1 to 12.0% by weight, preferably 0.5 to 10.5% by weight, more preferably 1.0 to 8.5% by weight, still more preferably 1.5 to 7.0% by weight and very particularly preferably 1.5 to 6.0% by weight of hydrogen peroxide, based on the weight of the medicament.

Persulfates are also preferably used in the medicament of the present invention in an amount within a certain range. It has been found that it is preferred that the medicament comprises (a) a total amount of 2.0 to 40.0 wt. -%, preferably 4.0 to 30.0 wt. -%, more preferably 6.0 to 20.0 wt. -% and most preferably 8.0 to 15.0 wt. -% of one or more persulfates selected from ammonium, potassium and sodium peroxodisulfate, based on the total weight of the medicament.

In the context of a particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises (a) one or more persulfates selected from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate in a total amount of 2.0 to 40.0 wt. -%, preferably 4.0 to 30.0 wt. -%, more preferably 6.0 to 20.0 wt. -% and most preferably 8.0 to 15.0 wt. -%, based on the total weight of the medicament.

Thus, in the context of another embodiment, particular preference is given to a medicament for lightening keratin fibres, in particular human hair, comprising, based on the total weight of the medicament

(a1) 0.1 to 12.0 wt.%, preferably 0.5 to 10.5 wt.%, more preferably 1.0 to 8.5 wt.%, still more preferably 1.5 to 7.0 wt.% and most preferably 1.5 to 6.0 wt.% of hydrogen peroxide, and

(a2) A total amount of 2.0 to 40 wt.%, preferably 4.0 to 30.0 wt.%, more preferably 6.0 to 20.0 wt.% and most preferably 8.0 to 15.0 wt.% of one or more persulfates selected from the group consisting of ammonium, potassium and sodium peroxodisulfate, and

(b) At least one complexing agent of the general formula (I),

wherein

(c) At least one free radical inhibitor.

Complexing agent (b)

As a second essential constituent of the invention, the agents according to the invention comprise at least one complexing agent (b) of the general formula (I),

wherein

M ₁ 、M ₂ independently of one another, represents a hydrogen atom, or the equivalent of an alkali metal, alkaline earth metal or metal ion, preferably sodium, potassium, 1/2 magnesium, 1/2 calcium, 1/2 zinc or ammonium ion (NH) ₄ ⁺ )。

The complexing agent of formula (I) is described as biodegradable and therefore represents an ecologically advantageous alternative to HEDP and EDTA. Surprisingly, it has been found that the use of these specific complexing agents (b) in the agents of the invention also greatly improves the lightening performance.

The substituents R mentioned in formula (I) ₁ 、R ₂ And R ₃ Examples of (a) are as follows:

C ₁ -C ₆ examples of alkyl groups include-CH ₃ 、-CH ₂ CH ₃ 、-CH ₂ CH ₂ CH ₃ 、-CH(CH ₃ ) ₂ 、-CH ₂ CH(CH ₃ ) ₂ 、-CH(CH ₃ )CH ₂ CH ₃ 、-C(CH ₃ ) ₃ 、-(CH ₂ ) ₄ CH ₃ 、-(CH ₂ ) ₅ CH ₃ . Particularly preferred alkyl groups are methyl and ethyl. C ₁ -C ₆ Examples of-hydroxyalkyl include-CH ₂ OH、-CH ₂ CH ₂ OH、-CH ₂ CH ₂ CH ₂ OH、-CH ₂ CH(OH)CH ₃ 、-CH ₂ CH ₂ CH ₂ CH ₂ OHIs preferably-CH ₂ CH ₂ OH。

carboxy-C ₁ -C ₆ An example of an alkyl group is HOOC-CH ₂ -、HOOC-CH ₂ -CH ₂ -、HOOC-CH ₂ -CH ₂ -CH ₂ -、HOOC-CH ₂ -CH ₂ -CH ₂ -CH ₂ -, of which HOOC-CH is preferred ₂ -a group.

In the complexing agent of the formula (I), the radical R ₁ Is a hydrogen atom, C ₁ -C ₆ -alkyl, hydroxy-C ₂ -C ₆ Alkyl, carboxy-C ₁ -C ₆ -alkyl or physiologically acceptable carboxy-C ₁ -C ₆ -a salt of an alkyl group.

Physiologically acceptable salts are salts which can be used in cosmetics under physiological conditions without side effects. carboxy-C ₁ -C ₆ Examples of physiologically acceptable salts of alkyl groups include carboxy-C ₁ -C ₆ Sodium, potassium and ammonium salts of alkyl groups.

A particularly strong improvement in the hair lightening performance is observed with agents comprising at least one complexing agent (b) of the general formula (I), wherein R ₁ Is a hydrogen atom, a carboxyl group-C ₁ -C ₆ Alkyl or a physiologically acceptable salt thereof, preferably a hydrogen atom, carboxymethyl or a physiologically acceptable salt thereof.

In the context of a particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one complexing agent (b) of the general formula (I), where

R ₁ Represents a hydrogen atom, a carboxyl group-C ₁ -C ₆ Alkyl or a physiologically acceptable salt thereof, preferably a hydrogen atom, carboxymethyl or a physiologically acceptable salt thereof.

In the complexing agent of the general formula (I), R ₂ And R ₃ Independently of one another, a hydrogen atom, C ₁ -C ₆ Alkyl, hydroxy-C ₂ -C ₆ Alkyl, carboxy-C ₁ -C ₆ Alkyl or a physiologically acceptable salt thereof.

Furthermore, when at least one of the radicals R is used in the medicament according to the invention ₂ And R ₃ Particularly good results are obtained in the lightening test when the complexing agents (b) of formula (I) represent, independently of one another, a hydrogen atom, a methyl group, a carboxymethyl group or a physiologically acceptable salt thereof.

R ₂ 、R ₃ Independently of one another, represents a hydrogen atom, a methyl group, a carboxymethyl group or a physiologically acceptable salt thereof.

The best hair lightening results are obtained with the complexing agent (b) of formula (I), wherein

R ₁ Is a carboxymethyl group or a physiologically acceptable salt thereof,

R ₂ represents a methyl group and

R ₃ represents a hydrogen atom.

R ₁ Is a carboxymethyl group or a physiologically acceptable salt thereof,

R ₂ represents a methyl group and

R ₃ represents a hydrogen atom.

A clear very particularly preferred complexing agent (b) of this embodiment is N, N-bis (carboxymethyl) -L-alanine, which may also be referred to as 2-methyl-2 ',2",2"' -nitrilotriacetic acid, abbreviated to the substance MGDA. MGDA has CAS number 29578-05-0, and is available from various suppliers, such as ABC Rabtory Scientific Co. Ltd, chemieliva Pharmaceutical Co. Ltd, SIA "Chemspace" or hong Kong Chemhere Co. Ltd, and has formula (I-a). Physiologically compatible salts of MGDA are also in accordance with the invention.

Furthermore, very good bleaching results are obtained with the complexing agent (b) of the formula (I), where

R ₁ Represents a hydrogen atom, and is represented by,

R ₂ and R ₃ Independently of one another, carboxymethyl or a physiologically acceptable salt thereof.

In the context of another particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one complexing agent (b) of the general formula (I), where

R ₁ Represents a hydrogen atom, and is represented by,

A specific very particularly preferred complexing agent (b) of this embodiment is aspartic acid-N- (2, 3-dicarboxyethyl) tetrasodium salt, which is also known as tetrasodium iminodisuccinate and has a CAS number of 144538-83-0. The complexing agent is commercially available from Lanxess under the tradename Baypure CX 100. Aspartic acid-N- (2, 3-dicarboxyethyl) tetrasodium salt having the formula (I-b)

In the compound of the formula (I-b), M ₁ And M ₂ The radicals all represent sodium cations. Tetrasodium salts and other salts, such as tetrapotassium salts, as well as the tetracarboxylic acids themselves, are also in accordance with the invention and are very particularly preferred.

Another suitable complexing agent of formula (I) is nitrilotriacetic acid (NTA). In the case of nitrilotriacetic acid,

R ₁ is carboxymethyl or a physiologically acceptable salt thereof, and

R ₂ 、R ₃ all represent hydrogen atoms.

In order to optimize the lightening or lightening effect, the complexing agent (b) is preferably used in the medicament according to the invention in an amount within a specific range.

Experiments with the prior art complexing agent HEDP (hydroxyethylphosphonic acid, CAS No. 2809-21-4) have shown that an increase in the amount of HEDP used does not necessarily lead to an improvement in the lightening performance. Therefore, the use of HEDP cannot improve the lightening property precisely by increasing the amount.

In the context of the results of known HEDP, it is not expected that other dose-activity ratios of the complexing agent (b) according to the invention will exist. However, it has now surprisingly been found that the complexing agent (b) according to the invention further improves the lightening effect when higher amounts are applied in the medicament.

It is therefore particularly preferred that the medicament comprises a total amount of 0.05 to 10.0 wt. -%, preferably 0.2 to 7.5 wt. -%, more preferably 1.0 to 5.0 wt. -% and most preferably 1.1 to 4.5 wt. -% of one or more complexing agents (b) of formula (I), based on the total weight of the medicament.

In the context of a particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises one or more complexing agents (b) of the formula (I) in a total amount of from 0.05 to 10.0% by weight, preferably from 0.2 to 7.5% by weight, more preferably from 1.0 to 5.0% by weight and very particularly preferably from 1.1 to 4.5% by weight, based on the total weight of the medicament.

Free radical inhibitor (c)

By using the complexing agent (b) according to the invention, HEDP or EDTA, which are the complexing agents commonly used in many commercial products, can be replaced without any loss of hair-lightening properties. However, experiments leading to the present invention have shown that the use of complexing agent (b) alone leads to greater hair damage and, in addition, also has a negative effect on the temperature profile of the hair dye. Thus, tests on hair tresses have shown that hair lighteners comprising only complexing agent (b) heat much more rapidly when applied to metal-contaminated hair than corresponding hair lighteners comprising HEDP or EDTA. Therefore, when applied to the head, a hair dye comprising only the complexing agent (b) may be significantly overheated.

In further experiments, it has now been found that the addition of at least one free radical inhibitor (c) both minimizes hair damage and greatly reduces the temperature generated when the agent is in contact with metal-containing hair. For this reason, the medicament according to the invention comprises at least one free-radical inhibitor (c) as an essential third component of the invention.

Lightening or lightening processes which occur on keratin fibres occur predominantly via free radical reactions, in which hydroxyl radicals formed from hydrogen peroxide and/or persulphates play a central role. A radical is an atom or molecule having at least one unpaired valence electron. In general, free radicals are characterized by very high reactivity.

For the purposes of the present invention, free radical inhibitors are substances which react with a reactive free radical, such as a hydroxyl radical, and convert it into a less reactive species by a series of rapid reactions, thereby interrupting the free radical chain reaction.

Free radical inhibitors suitable for use in cosmetics may fall into a particular category. The use of one or more free radical inhibitors selected from the group consisting of antioxidants, thiols, quinones and unsaturated organic compounds has proven particularly suitable for use in the lightening or dye lightening agents of the present invention.

In another particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (c) selected from the group consisting of unsaturated organic compounds, antioxidants, quinones and thiols.

It has proven particularly preferable to use at least one free-radical inhibitor (c) selected from unsaturated organic compounds in the inventive medicament for solving the problem according to the invention. Unsaturated organic compounds are understood to be organic compounds having at least one carbon-carbon double bond.

It has been demonstrated to use at least one mono-or polyunsaturated C ₈ -C ₃₀ Fatty acids and/or mono-or polyunsaturated C ₈ -C ₃₀ Derivatives of fatty acids are particularly advantageous.

According to the invention, the unsaturated fatty acids are mono-or polyunsaturated, unbranched or branched, unsubstituted or substituted C ₈ -C ₃₀ A carboxylic acid. The unsaturated fatty acid may be a mono-or polyunsaturated fatty acid. For unsaturated fatty acids, the C-C double bond may have either the cis or trans configuration.

In another particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one C selected from the group consisting of unsaturated C ₈ -C ₃₀ A free radical inhibitor of a fatty acid and derivatives thereof (c).

C ₈ -C ₃₀ Examples of unsaturated fatty acids include petroselinic acid [ (Z) -6-octadecenoic acid]Palmitoleic acid [ (9Z) -hexadec-9-enoic acid]Oleic acid [ (9Z) -octadec-9-enoic acid]And elaidic acid [ (9E) -octadec-9-enoic acid]Erucic acid [ (13Z) -docosal-13-olefine acid]Linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid]Linolenic acid [ (9Z, 12Z, 15Z) -octadeca-9, 12, 15-trienoic acid]The tung acid [ (9Z, 11E, 13E) -octadeca-9, 11, 3-trienoic acid]Arachidonic acid [ (5Z, 8Z,11Z, 14Z) -eicosa-5, 8,11, 14-tetraenoic acid]And/or nervonic acid [ (15Z) -tetracos-15-enoic acid]. Very particularly preferred unsaturated C ₈ -C ₃₀ The fatty acid is linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid, linolenic acid [ (9Z, 12Z, 15Z) -octadeca-9, 12, 15-trienoic acid.

In another particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free radical inhibitor (c) selected from the group consisting of [ (Z) -6-octadecenoic acid ] petroselinic acid]Palmitoleic acid [ (9Z) -hexadec-9-enoic acid]Oleic acid [ (9Z) -octadec-9-enoic acid]Trans-oleic acid [ (9E) -octadec-9-enoic acid]Erucic acid [ (13Z) -docosahexenoic acid]Linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid]Linolenic acid [ (9Z, 12Z, 15Z) -octadecanoic-9, 12, 15-trienoic acid]The tung acid [ (9Z, 11E, 13E) -octadeca-9, 11, 3-trienoic acid]Arachidonic acid [ (5Z, 8Z,11Z, 14Z) -eicosa-5, 8,11, 14-tetraenoic acid]And/or nervonic acid [ (15Z) -tetracos-15-enoic acid]. Very particularly preferred unsaturated C ₈ -C ₃₀ The fatty acid is linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid]Linolenic acid [ (9Z, 12Z, 15Z) -octadeca-9, 12, 15-trienoic acid]。

Particularly suitable unsaturated C ₈ -C ₃₀ Examples of fatty acids are linoleic and linolenic acids. These are essential fatty acids, also referred to in the literature as vitamin F.

In another very particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (c) selected from linoleic acid and linolenic acid.

C ₈ -C ₃₀ Fatty acidsParticularly suitable derivatives of (b) are their esters.

C ₈ -C ₃₀ Unsaturated fatty acid esters are characterized by the presence of an ester function obtained by esterification of the acid function of a fatty acid with an alcohol. The alcohol may be a mono-or polyol, which may also optionally bear additional functional groups or substituents.

Examples of monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, n-tetradecanol, n-hexadecanol, and n-octadecanol.

Examples of polyols are 1, 2-propanediol, 1, 3-propanediol and glycerol. Glycerol is particularly preferred.

C ₈ -C ₃₀ Other examples of esters of unsaturated fatty acids include the corresponding fatty acid monoglycerides, fatty acid diglycerides, and fatty acid triglycerides.

C ₈ -C ₃₀ The fatty acid monoglyceride is glycerol and one equivalent of unsaturated C ₈ -C ₃₀ Monoesters of fatty acids. Either the middle hydroxyl group of glycerol or the terminal hydroxyl group of glycerol may be esterified with a fatty acid.

C ₁₂ -C ₃₀ The hydroxyl group of glycerol in the fatty acid monoglyceride is esterified with fatty acid selected from petroselinic acid [ (Z) -6-octadecenoic acid]Palmitoleic acid [ (9Z) -hexadec-9-enoic acid]Oleic acid [ (9Z) -octadec-9-enoic acid]And elaidic acid [ (9E) -octadec-9-enoic acid]Erucic acid [ (13Z) -docosal-13-olefine acid]Linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid]Linolenic acid [ (9Z, 12Z, 15Z) -octadeca-9, 12, 15-trienoic acid]The tung acid [ (9Z, 11E, 13E) -octadeca-9, 11, 3-trienoic acid]Arachidonic acid [ (5Z, 8Z,11Z, 14Z) -eicosa-5, 8,11, 14-tetraenoic acid]Or nervonic acid [ (15Z) -tetracosen-15-enoic acid]。

C ₁₂ -C ₃₀ Fatty acid diglyceride is understood to be glycerol as the triol with two equivalents of C ₈ -C ₃₀ Diesters of fatty acids, at least one of which must be unsaturated C ₈ -C ₃₀ A fatty acid. The middle hydroxyl group and one terminal hydroxyl group of glycerolTwo equivalents of fatty acid may be used for esterification, or two terminal hydroxyl groups of glycerol may be esterified with one fatty acid each. Glycerol can be esterified with two structurally identical fatty acids or with two different fatty acids, provided that at least one fatty acid is unsaturated C ₈ -C ₃₀ A fatty acid.

Such fatty acid diglycerides are particularly suitable, wherein at least one ester group is formed by glycerol with a fatty acid selected from the group consisting of: petroselinic acid [ (Z) -6-octadecenoic acid ], palmitoleic acid [ (9Z) -hexadec-9-enoic acid ], oleic acid [ (9Z) -octadec-9-enoic acid ], elaidic acid [ (9E) -octadec-9-enoic acid ], erucic acid [ (13Z) -docosan-13-enoic acid ], linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid ], linolenic acid [ (9Z, 12Z, 15Z) -octadec-9, 12, 15-trienoic acid ], eleostearic acid [ (9Z, 111E, 13E) -octadec-9, 11, 3-trienoic acid ], arachidonic acid [ (5Z, 8Z, 11114Z, 14Z) -eicos-5, 8,11, 14-tetraenoic acid ] or nervonic acid [ (15Z) -tetracosan-15-enoic acid ].

C ₁₂ -C ₃₀ Fatty acid triglycerides are understood to be trihydric glycerol with three equivalents of C ₈ -C ₃₀ Triesters of fatty acids, at least one of which must be an unsaturated C ₈ -C ₃₀ A fatty acid. The glycerol may be esterified with three fatty acids having the same structure or with different fatty acids, provided that at least one fatty acid is an unsaturated C ₈ -C ₃₀ A fatty acid.

Fatty acid triglycerides in which at least one ester group is formed from glycerol and a fatty acid selected from: petroselinic acid [ (Z) -6-octadecenoic acid ], palmitoleic acid [ (9Z) -hexadec-9-enoic acid ], oleic acid [ (9Z) -octadec-9-enoic acid ], elaidic acid [ (9E) -octadec-9-enoic acid ], erucic acid [ (13Z) -docosene-13-enoic acid ], linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid ], linolenic acid [ (9Z, 12Z, 15Z) -octadeca-9, 12, 15-trienoic acid ], eleostearic acid [ (9Z, 111E, 13E) -octadeca-9, 11, 3-trienoic acid ], arachidonic acid [ (5Z, 8Z, 1114Z, 14Z) -eicosa-5, 8,11, 14-tetraenoic acid ] or nervonic acid [ (15Z) -tetracosan-15-enoic acid ].

Specifically, it has been demonstrated that free radical inhibitors (c) from the phosphoglyceride type are particularly suitable for solving the problem of the present invention. PhosphoglycerideBelong to C ₈ -C ₃₀ Fatty acid ester types.

In this context, a phosphoglyceride according to the invention is understood to be a substance which can also be referred to as glycerophospholipide/phosphoglyceride.

Phosphoglycerides in the sense of the present invention consist of two C's at two of the hydroxyl groups (OH groups) of glycerol ₈ -C ₃₀ Fatty acid esterified glycerol, provided that at least one fatty acid is unsaturated C ₈ -C ₃₀ A fatty acid. The phosphate group is attached to one of the third OH groups, i.e., the terminal OH group. The phosphate group is in turn esterified with different alcohols. The phosphate group forms a phosphodiester.

Specifically, free radical inhibitors (c) from the lecithin type are particularly preferred.

In the context of another explicitly very particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (c) of the general formula (II):

wherein

R ₄ 、R ₅ Independently of one another denote saturated or unsaturated C ₁₁ -C ₂₉ Alkyl, provided that R is ₄ And R ₅ At least one of them represents unsaturated C ₁₁ -C ₂₉ An alkyl group.

Preferably, R ₄ And/or R ₅ The group may represent the following group. The radical together with R ₄ Or R ₅ The adjacent carbonyl groups of the groups together form the esterified form of the fatty acid given in the table below:

preferably, the group R ₄ And/or R ₅ At least one of (A) represents at least monounsaturated C ₁₆ -C ₂₀ Alkyl, particularly preferably represents at least diunsaturated C ₁₆ -C ₂₀ Alkyl and definitely most preferably represents at least tri-unsaturated C ₁₆ -C ₂₀ An alkyl group.

In another explicitly very particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (c) of the general formula (II) in which the radical R is ₄ And/or R ₅ Is at least monounsaturated C ₁₅ -C ₂₁ Alkyl, particularly preferably at least diunsaturated C ₁₅ -C ₂₁ Alkyl and specifically very particularly preferably at least tri-unsaturated C ₁₅ -C ₂₁ An alkyl group.

In the context of another explicitly very particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one radical inhibitor (c) of the general formula (II) in which the radical R is ₄ And/or R ₅ At least one of them represents a diunsaturated C ₁₇ Alkyl or tri-unsaturated C ₁₇ An alkyl group.

If R remains ₄ Or R ₅ One of them being saturated C ₁₁ -C ₂₉ Alkyl, then the radical may preferably be saturated C ₁₁ Alkyl, saturated C ₁₃ Alkyl, saturated C ₁₅ Alkyl, saturated C ₁₇ Alkyl, saturated C ₁₉ Alkyl or saturated C ₂₁ An alkyl group.

One particularly suitable lecithin of formula (II) is soybean lecithin, which is commercially available from the company Lipoid GmbH under the trade name Lipoid P20. The starting material has a phosphatidylcholine (= lecithin) content of at least 20 wt%, wherein at least 61 wt% of the fatty acids are linoleic or linolenic acid, based on the total content of fatty acids obtained after hydrolysis of the lecithin.

As free radical inhibitors (C) from the antioxidant class, vitamin F, vitamin E, vitamin C, vitamin a, vitamin B and vitamin H have proven to be particularly suitable.

And (3) vitamin F: the term vitamin F as mentioned above generally refers to essential fatty acids, especially linoleic acid, linolenic acid.

Vitamin E: vitamin E is a generic term for fat-soluble substances that have a major antioxidant effect. The most abundant forms of vitamin E are known as tocopherols and tocotrienols. As a particularly suitable vitamin E, alpha-tocopherol can be used.

Alpha-tocopherol is also known as (2R) -2,5,7, 8-tetramethyl-2- [ (4R, 8R) -4,8, 12-trimethyltridecyl ] -3, 4-dihydro-2H-benzopyran-6-ol or E307 and has the CAS number 10191-41-0.

The class of substances known as vitamin A includes retinol (vitamin A1) and 3, 4-didehydro retinol (vitamin A2). Beta-carotene is the provitamin of retinol. Vitamin a components which may be considered according to the invention are, for example, tretinoin and its esters, tretinoin and tretinol and their esters such as palmitate and acetate.

Also suitable according to the invention are vitamin C (ascorbic acid) and its esters, especially ascorbyl palmitate.

Vitamin B types or vitamin B complexes include the following, among others:

vitamin B ₁ (thiamine)

Vitamin B ₂ (Riboflavin)

Vitamin B ₃ . The compounds nicotinic acid and nicotinamide (nicotinamide) are often listed under this name, with nicotinamide being particularly preferred according to the invention.

Vitamin B ₅ (pantothenic acid and panthenol). In this type, panthenol is preferred. Panthenol derivatives which can be used according to the invention are in particular esters and ethers of panthenol, cationically derivatized panthenol and pantolactone.

Vitamin B ₆ (pyridoxine and pyridoxine)Amines and pyridoxal).

Vitamin H. The compound (3aS, 4S, 6aR) -2-oxohexahydrothieno [3,4-d ] -imidazole-4-pentanoic acid is called vitamin H, but is widely known under the common name biotin.

In the context of another preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (C) selected from the group consisting of vitamin F, vitamin E, vitamin C, vitamin a, vitamin B and vitamin H.

In the context of another particularly preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one free-radical inhibitor (C) selected from vitamin F, vitamin E, vitamin C and vitamin a.

Compounds from the quinone type are suitable as free radical inhibitors (c). Quinones are organic compounds having a quinoid system. Suitable representatives of the quinone type are 1, 4-benzoquinone, 1, 4-naphthoquinone, 2-hydroxy-1, 4-naphthoquinone. Also suitable are compounds with at least one group such as hydroxyl, amino, nitro, carboxylic acid, C ₁ -C ₆ Alkyl radical, C ₁ -C ₆ 1, 4-benzoquinone and 1, 4-naphthoquinone as substituents of the alkoxy group.

Examples of suitable free radical inhibitors (c) from the thiol type are thiolactic acid, ammonium thioglycolate and ammonium thiolactate.

Thiolactic acid is understood to mean D-thiolactic acid, L-thiolactic acid and/or mixtures thereof. Cysteine is understood as meaning D-cysteine, L-cysteine and/or mixtures thereof.

Ammonium thioglycolate is the ammonium salt of thioglycolic acid (i.e. the ammonium salt of thioglycolic acid) (formula Thiol-I)

Ammonium thiolactate is an ammonium salt of thiolactic acid (i.e., an ammonium salt of 2-mercaptopropionic acid) (formula Thiol-II).

The definition of ammonium thiolactate includes ammonium salts of D-thiolactic acid and salts of L-thiolactic acid and mixtures thereof.

In order to optimize the desired effect, it is also preferred that the free radical inhibitor (c) is used in the medicament of the invention in an amount within a specific range. It has been found to be particularly advantageous that the medicament comprises one or more free radical inhibitors (c) in a total amount of 0.01 to 10.0 wt. -%, preferably 0.25 to 7.0 wt. -%, more preferably 0.25 to 6.0 wt. -% and most preferably 0.25 to 2.5 wt. -%, based on the total weight of the medicament.

In another preferred embodiment, the medicament according to the invention is characterized in that it comprises one or more free-radical inhibitors (c) in a total amount of 0.01 to 10.0% by weight, preferably 0.25 to 7.0% by weight, more preferably 0.25 to 6.0% by weight and very particularly preferably 0.25 to 2.5% by weight, based on the total weight of the medicament.

Alkalizing agent

As described above, the agent according to the first invention of the present invention is a ready-to-use agent for lightening or dyeing keratin fibers. In order to achieve a sufficient lightening effect, such agents are usually strongly alkaline, preferably at a pH between 9 and 10.5. Such high pH values are necessary to ensure that the outer cuticle layer is opened and thus to allow the penetration of the active substances (hydrogen peroxide and persulfate salts) into the hair.

For this reason, it has been found to be particularly preferred that the medicament according to the invention additionally comprises at least one basifying agent.

Within the context of another preferred embodiment, the medicament according to the invention is characterized in that it comprises at least one basifying agent.

Preferred alkalizing agents are, for example, ammonia, alkanolamines, basic amino acids and inorganic alkalizing agents, such as alkali (earth) metal hydroxides, alkali (earth) metal metasilicates, alkali (earth) metal silicates, alkali (earth) metal phosphates and alkali (earth) metal hydrogenphosphates. Preferred metal ions are lithium, sodium and/or potassium. Preferred alkalinizing agents are alkali (earth) metasilicates and alkali (earth) metasilicates.

Suitable inorganic alkalizing agents are preferably selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium phosphate, potassium phosphate, sodium silicate, potassium silicate, magnesium silicate, sodium carbonate and potassium carbonate. Sodium hydroxide and/or potassium hydroxide are particularly preferred.

The alkanolamines as alkalinizing agents are preferably chosen from those having C with at least one hydroxyl group ₂ -C ₆ Primary, secondary or tertiary amines of the alkyl precursor. Particularly preferred alkanolamines are selected from the group consisting of 2-aminoethan-1-ol (monoethanolamine), 3-aminopropan-1-ol, 4-aminobutan-1-ol, 5-aminopentan-1-ol, 1-aminopropan-2-ol (monoisopropanolamine), 1-aminobutan-2-ol, 1-aminopentan-3-ol, 1-aminopentan-4-ol, 2-amino-2-methyl-propanol, 2-amino-2-methylbutanol, 3-amino-2-methylpropan-1-ol, 1-amino-2-methylpropan-2-ol, 3-aminopropan-1, 2-diol, 2-amino-2-methylpropan-1, 3-diol, 2-amino-2-ethyl-1, 3-propanediol, N-dimethylethanolamine, methylglucamine, triethanolamine, diethanolamine and triisopropanolamine. Particularly preferred alkanolamines are monoethanolamine, 2-amino-2-methyl-propanol and triethanolamine.

The basic amino acid as the alkalinizing agent is preferably selected from the group consisting of L-arginine, D/L-arginine, L-lysine, D/L-lysine, L-ornithine, D/L-ornithine, L-histidine, D-histidine and/or D/L-histidine. L-arginine, D-arginine and/or D/L-arginine are particularly preferred as alkalizing agents.

Abandoning HEDP or EDTA

The object of the present application is in particular to dispense with the non-biodegradable complexing agents HEDP and EDTA. For this reason, the medicament according to the invention preferably comprises particularly small amounts of these two complexing agents. Very preferably, the medicament does not contain both substances. Most preferably, the agent is also substantially free of salts of HEDP and EDTA.

In a further preferred embodiment, the medicament according to the invention is characterized in that the total content of hydroxyethylphosphonic acid and hydroxyethylphosphonate contained in the medicament is less than 0.2% by weight, preferably less than 0.1% by weight, more preferably less than 0.05% by weight and very particularly preferably less than 0.001% by weight, based on the total weight of the medicament.

In a further preferred embodiment, the medicament according to the invention is characterized in that the medicament contains less than 0.2% by weight, preferably less than 0.1% by weight, more preferably less than 0.05% by weight and very particularly preferably less than 0.001% by weight of EDTA and EDTA salts, based on the total weight of the medicament.

Hydroxyethylphosphonic acid is also known as hydroxyethane-1, 1-diphosphonic acid and CAS number 2809-21-4.

EDTA is also known as ethylenediaminetetraacetic acid and CAS numbers 6381-92-6 and 139-33-3 (anhydrous).

Other ingredients

In addition to the components (a), (b) and (c) essential to the invention and optionally an alkalizing agent, the medicament according to the invention may also comprise other active ingredients and auxiliaries as optional components. These are described below.

The medicament may also contain other active ingredients, adjuvants and additives, such as solvents, fatty components, e.g. C ₈ -C ₃₀ Fatty alcohol, C ₈ -C ₃₀ Fatty acid triglyceride, C ₈ -C ₃₀ Fatty acid monoglyceride, C ₈ -C ₃₀ Fatty acid diglycerides and/or hydrocarbons; nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric and/or zwitterionic surfactants, polymers; structuring agents such as glucose, maleic acid and lactic acid, hair conditioning compounds such as phospholipids, e.g. lecithin and cephalin; perfume oil, dimethyl isosorbide and cyclodextrin; texturizing agents, in particular mono-, di-and oligosaccharides, such as glucose, galactose, fructose (fructose) and lactose; a dye for coloring the agent; antidandruff agents such as piroctone olamine, zinc pyrithione, and dryobalide; amino acids and oligopeptides; animal-and/or plant-based protein hydrolysates, and also in the form of their fatty acid condensation products or, if appropriate, anionically or cationically modified derivatives;a vegetable oil; light stabilizers and UV blockers; active ingredients such as panthenol, pantothenic acid, pantolactone, allantoin, pyrrolidone carboxylic acid and their salts and bisabolol; polyphenols, in particular hydroxycinnamic acids, 6, 7-dihydroxycoumarins, hydroxybenzoic acids, plant extracts; fats and waxes such as fatty alcohols, beeswax, montan wax, and paraffin wax; swelling and penetrating agents such as glycerol, propylene glycol monoethyl ether, carbonates, bicarbonates, guanidines, ureas, and primary, secondary, and tertiary phosphates; opacifying agents such as latex, styrene/PVP, and styrene/acrylamide copolymers; pearlizing agents such as ethylene glycol mono-and distearate and PEG-3 distearate; and blowing agents, such as propane-butane mixtures, N ₂ O, dimethyl ether, CO ₂ And air.

The selection of these other substances will be made by the expert according to the desired properties of the medicament. With regard to the other optionally present components and the amounts of these components, reference is explicitly made to the relevant manual known to the expert. The further active ingredients and auxiliaries are preferably used in the formulations according to the invention in amounts of from 0.0001 to 25% by weight, in particular from 0.0005 to 15% by weight, each, based on the total weight of the corresponding medicament.

Keratin fibre lightening method

As previously mentioned, the agents of the first subject of the invention present a ready-to-use lightening or hair-lightening agent which, in addition to the oxidizing agent (a), comprises a complexing agent (b), a free-radical inhibitor (c) and optionally an alkalinizing agent.

Oxidizers such as hydrogen peroxide and persulfates are highly active compounds that have limited stability, especially in alkaline environments. For this reason, ready-to-use hair lighteners are generally prepared by mixing two or more separately packaged formulations prior to use.

Typically, the oxidizing agent (a) and the alkalizing agent are prepared separately. It is now possible to envisage different types of packaging for the complexing agent (b) and the free-radical inhibitor (c).

For example, the complexing agent (b) and the free radical inhibitor (c) may be combined with one or more persulfates, but separated from the hydrogen peroxide. This embodiment is particularly preferred when only two different formulations are mixed together to produce a ready-to-use medicament.

Another subject of the invention is a process for lightening keratin fibres, characterized in that at least two separately packaged formulations (A) and (B) are mixed to form an application mixture, the application mixture being applied to the fibres and rinsed off again after a contact time, wherein

-the formulation (a) comprises hydrogen peroxide (a 1), and

-formulation (B) comprises

-at least one persulfate (a 2) selected from ammonium, potassium and sodium peroxodisulfate, and

comprising at least one complexing agent (b) of the general formula (I) and

-comprises at least one free radical inhibitor (c),

wherein the complexing agent (b) and the radical inhibitor (c) have been disclosed in detail in the description of the first subject-matter of the present invention.

Formulations (a) and (B) may be mixed with each other just prior to use, or may be mixed with other separately packaged formulations to form an application mixture.

If three different formulations are mixed together to produce a ready-to-use medicament, it may be preferred to provide the first oxidizing agent hydrogen peroxide separately in the first formulation (A), the persulfate salt separately as the second oxidizing agent in the second formulation (B), and a third formulation (C) comprising the complexing agent (B) and the free-radical inhibitor (C).

Another object of the present invention is a process for lightening keratin fibres, characterized in that at least three separately packaged formulations (A), (B) and (C) are mixed to form an application mixture, the application mixture being applied to the fibres and rinsed off again after a contact time, wherein

-the formulation (a) comprises hydrogen peroxide (a 1), and

-the preparation (B) comprises at least one persulfate (a 2) selected from ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate,

-the preparation (C) comprises at least one complexing agent (b) of the general formula (I) and at least one free-radical inhibitor (C),

wherein the complexing agent (b) and the radical inhibitor (c) have been disclosed in detail in the description of the first subject matter of the present invention.

The persulfate-containing formulation (B) is preferably in powder form. Powders of solid components having different particle sizes may be used. However, it is generally preferred that the powder has a particle size which is as uniform as possible, in particular in order to promote uniform dispersion or dissolution of the powder in the formulation (B).

In addition, formulation (B) may also comprise persulfate salts in solid cosmetic carriers. The solid cosmetic carrier may comprise salts of silicic acid, in particular silicic and metasilicic acids with ammonium, alkali metals and alkaline earth metals. In particular, the compounds according to formula (SiO) may be preferably used ₂ ) _n (M ₂ O) _m Characterized in that the ratio between n and M is ≦ 1, where M represents an ammonium ion, an alkali metal or a semi-stoichiometric equivalent of an alkaline earth metal, and may be understood as an anion [ SiO ₃ ] ^2- The chain-like polymeric structure of (3). Formula [ Na ] ₂ SiO ₃ ] _∞ Sodium metasilicate of (a) is particularly preferred. Also preferred is a compound of formula (SiO) ₂ ) _n (Na ₂ O) _m (K ₂ O) _p Wherein n is a positive rational number and m and p are independently a positive rational number or 0, with the proviso that at least one of the parameters m or p is not 0 and the ratio between n and the sum of m and p is between 2 and 4.

Furthermore, the solid formulation (B) may comprise so-called anti-caking agents, which are intended to prevent caking or caking of the powder ingredients. Preferably, water-insoluble, hydrophobic or hygroscopic powders of diatomaceous earth, fumed silica, calcium phosphate, calcium silicate, alumina, magnesium oxide, magnesium carbonate, zinc oxide, stearates, fatty amines, and the like are suitable as such anticaking agents.

Finally, the formulation (B) may additionally comprise a dedusting agent which prevents the powder components from forming dust. Inert oils are particularly useful for this purpose. Preferably, the solid cosmetic carrier comprises an ester oil or a mineral oil, preferably a hydrocarbon oil such as liquid paraffin, as a dedusting agent.

The ready-to-use formulation is prepared immediately before application to the hair by mixing two of the formulations (a) and (B) or by mixing the three formulations (a) and (B) and (C). For a ready-to-use formulation where more than two formulations are mixed to form the final application mix, it may be irrelevant whether the two formulations are mixed together first and then the third formulation is added and mixed in, or whether all formulations are combined together and then mixed. Mixing can be accomplished by stirring in a bowl or cup or shaking in a sealable container.

The term "immediately" is understood to mean a period of time of from a few seconds to an hour, preferably up to 30 minutes, in particular up to 15 minutes.

The formulations (A), (B) and optionally (C) are used in a method for lightening keratin fibres, in particular human hair, in which the agent is applied to the keratin fibres, left on the fibres for a period of from 10 to 60 minutes and then rinsed off again with water or shampooed.

Preferably, the contact time of the ready-to-use shallowing agent is from 10 to 60 minutes, in particular from 15 to 50 minutes, particularly preferably from 20 to 45 minutes. It may be advantageous to support the whitening process by applying a small amount of heat during the contact time of the medicament on the fibers. The heat may be provided by an external heat source, such as by a hot air blower, or by the body temperature of the subject, particularly in the case of hair lightening of a living subject. For the latter option, the area to be shallowly covered is typically covered with a hat. The contacting stage is preferably carried out at room temperature.

After the contact time has ended, the remaining lightening agent is rinsed off from the hair with water or a detergent. In particular, commercially available shampoos can be used as the cleansing agent, although if the lightening agent has a carrier containing a high level of surfactant, the cleansing agent can be dispensed with and the rinsing process can be carried out with tap water.

Preferred embodiments of the above-described agents are suitable for use in the method, with appropriate modification.

Examples

1. A ready-to-use whitening agent is prepared by mixing the three formulations (A), (B) and (C).

The following formulations were prepared (all data are expressed in weight% unless otherwise noted).

Preparation (A)	By weight%
		Disodium pyrophosphate	0.1
Pyridinedicarboxylic acids	0.1
		Potassium hydroxide (50% aqueous solution)	0.3
Cetearyl alcohol	3.6
		Ceteareth-20	0.5
Sodium dodecyl sulfate	0.3
		PEG-40 Castor oil	0.6
Myristic acid isopropyl ester	10.0
		Hydrogen peroxide, 50% aqueous solution	23.2
Water (I)	To add to 100

Preparation (B)	By weight%
		Potassium persulfate	98.4
Silicon dioxide (gas phase process)	1.4

MGDA: n, N-bis (carboxymethyl) -L-alanine CAS No. 29578-05-0

And (3) vitamin F: linoleic acid, linolenic acid (Polichimica), CAS No. 1106-87-4

Lipid P20: soybean lecithin CAS number 8030-76-0, lipoid GmbH Ludwigshafen

2. Dyeing process

The measurement was carried out colorimetrically (Datacolor Spectraflash SF 450) on a hair strand (Kerling, euronaturar 4-0) previously shampooed and dried.

To prepare a ready-to-use lightening or hair-coloring agent, 60g of formulation (A) were mixed in each case with 20g of formulation (B) and 60g of formulation (C). The resulting application mixture was applied to the hair strand, left for 45 minutes and then rinsed again with water. Thereafter, the hair tresses are measured again colorimetrically.

The higher the Δ L value, the greater the lightening of the hair strand compared to untreated hair.

The higher the Δ Ε value, the greater the color shift of the hair tresses compared to untreated hair.

3. Measurement of temperature profile during shallowing

The temperature occurring during the lightening was measured with hair tresses having a high metal content. To produce the hair strand, the following treatments were performed:

the hair tresses were previously washed with shampoo (Kerling, euronarwhite, 6-0) and then pre-dyed once with a commercial lightening agent. The purpose of the pre-dyeing of the light hair is to increase the copper uptake in the hair. The tresses of hair thus pre-dyed with shallow hair were doped with copper:

for this purpose, 1g of hair tresses were immersed in 40g of copper solution (50 ppm copper in water, 16.8 ℃ dH) each time and left for 1 minute. The tress was then removed from the solution, gently squeezed and stored at room temperature. This dipping process was repeated three times for each hair strand.

The copper content of each strand was then determined analytically. Using atomic emission spectroscopy (ICP-OES) with HNO ₃ The measurement was carried out after mineralisation of the samples (one beam at a time) in the microwave digestion system of/HCL. The average was calculated from 12 measurements. The average copper content of each strand was 3900mg/kg.

The application mixtures described in item 2 are applied to the hair treated in this way. The hair tresses were equipped with Pt100 probes and wrapped in aluminum foil. The reaction temperature was measured and recorded every 5 minutes.

The application mixtures according to the invention become less warm during application and therefore exhibit more favorable temperature behavior.

After 45 minutes, the application mixture was rinsed off the respective hair strand with water. The tress is then dried.

4. Measurement of cysteine content

The tresses lightened in item 3 were used to measure hair damage. Hair damage was determined by quantitative NIR spectroscopy of hair that was lightened as described previously.

With MPA from Bruker Optik GmbH ^{TM FT} NIR Spetkromer records spectra. The infrared region covers from 12500cm ^-1 To 4000cm ^-1 And is characterized by, for example, broad frequencies and combined vibrations of CH, OH and NH groups.

The measurement of the sample was performed using integrating sphere modeling for diffuse reflectance at six different sample positions. For the analysis of the measured NIR spectra, an index of 7300cm was chosen ^-1 To 4020cm ^-1 The wavenumber range of (2).

NIR spectra of cysteine are shown at 6200cm ^-1 To 5500cm ^-1 Characteristic absorption band in the wavenumber range of (c). If the hair changes due to more severe damage (i.e. increased cysteine content in the hair), this will affect 5020cm in the NIR spectrum ^-1 To 4020cm ^-1 The band characteristic of cysteine. Quantitative assessment of NIR spectra was computer-assisted.

NIR analysis [ mol cysteine/100 mol amino acid ].

A reduction in hair damage was measured with the application mixture according to the invention.

5. Other formulation examples

A ready-to-use lightening agent is prepared by mixing the two formulations (A) and (B).

Preparation (A)	By weight%
		Disodium pyrophosphate	0.1
Pyridinedicarboxylic acids	0.1
		Potassium hydroxide (50% aqueous solution)	0.3
Cetostearyl alcohol	3.6
		Ceteareth-20	0.5
Sodium dodecyl sulfate	0.3
		PEG-40 Castor oil	0.6
Myristic acid isopropyl ester	10.0
		Hydrogen peroxide, 50% aqueous solution	23.2
Water (W)	To 100 of

A ready-to-use bleaching agent is prepared by mixing the formulation (a) with one of the formulations (B1) to (B8).

A ready-to-use shallowing agent is prepared by mixing the formulation (a) with one of the formulations (B9) to (B12).

Claims

1. An agent for lightening keratin fibres, in particular human hair, comprising

(a) At least one oxidizing agent, wherein the oxidizing agent is selected from the group consisting of,

(b) At least one complexing agent of the general formula (I),

wherein

(c) At least one free radical inhibitor.

2. The pharmaceutical formulation of claim 1, wherein said pharmaceutical formulation comprises

3. The agent according to any one of claims 1 to 2, characterized in that it comprises

(a1) Hydrogen peroxide and

4. The medicament of any one of claims 1 to 3, wherein the medicament comprises (a) 0.1 to 12.0 wt. -%, preferably 0.5 to 10.5 wt. -%, more preferably 1.0 to 8.5 wt. -%, still more preferably 1.5 to 7.0 wt. -%, and most preferably 1.5 to 6.0 wt. -% of hydrogen peroxide based on the weight of the medicament.

5. The medicament according to any one of claims 1 to 4, characterized in that it comprises (a) one or more persulfates selected from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate in a total amount of 2.0 to 40.0 wt. -%, preferably 4.0 to 30.0 wt. -%, more preferably 6.0 to 20.0 wt. -% and most preferably 8.0 to 15.0 wt. -%, based on the total weight of the medicament.

6. The agent according to any one of claims 1 to 5, characterized in that it comprises at least one complexing agent (b) of general formula (I), wherein

7. The agent according to any one of claims 1 to 6, characterized in that it comprises at least one complexing agent (b) of general formula (I), wherein

8. The agent according to any one of claims 1 to 7, characterized in that it comprises at least one complexing agent (b) of general formula (I), wherein

R ₁ Is a carboxymethyl group or a physiologically acceptable salt thereof,

R ₂ represents a methyl group and

R ₃ represents a hydrogen atom.

9. The agent according to any one of claims 1 to 8, characterized in that it comprises at least one complexing agent (b) of general formula (I), wherein

R ₁ Represents a hydrogen atom, and is represented by,

10. The medicament according to any one of claims 1 to 9, characterized in that it comprises one or more complexing agents (b) of formula (I) in a total amount of 0.05 to 10.0 wt. -%, preferably 0.2 to 7.5 wt. -%, more preferably 1.0 to 5.0 wt. -%, and most preferably 1.1 to 4.5 wt. -%, based on the total weight of the medicament.

11. The agent according to any one of claims 1 to 10, characterized in that it comprises at least one radical inhibitor (c) selected from unsaturated organic compounds, antioxidants, quinones and thiols.

12. The agent according to any one of claims 1 to 11, characterized in that it comprises at least one unsaturated C selected from ₈ -C ₃₀ A free radical inhibitor (c) of a fatty acid or a derivative thereof.

13. Agent according to any one of claims 1 to 12, characterized in that it comprises at least one free radical inhibitor (c) selected from the group consisting of: petroselinic acid [ (Z) -6-octadecenoic acid ], palmitoleic acid [ (9Z) -hexadec-9-enoic acid ], oleic acid [ (9Z) -octadec-9-enoic acid ], elaidic acid [ (9E) -octadec-9-enoic acid ], erucic acid [ (13Z) -docosan-13-enoic acid ], linoleic acid [ (9Z, 12Z) -octadeca-9, 12-dienoic acid ], linolenic acid [ (9Z, 12Z, 15Z) -octadec-9, 12, 15-trienoic acid ], eleostearic acid [ (9Z, 111E, 13E) -octadec-9, 11, 3-trienoic acid ], arachidonic acid [ (5Z, 8Z, 111Z, 14Z) -eicos-5, 8,11, 14-tetraenoic acid ], and nervonic acid [ (15Z) -tetracosan-15-enoic acid ], most preferably linoleic acid [ (9Z, 12Z) -octadecadienoic acid ] and [ (Z, 12Z) -octadecatrienoic acid, 12-15, 12, 15-trienoic acid.

14. The agent according to any one of claims 1 to 13, characterized in that it comprises at least one radical inhibitor (c) of general formula (II):

wherein

R ₄ 、R ₅ Independently of one another represent saturated or unsaturated C ₁₁ -C ₂₉ Alkyl, provided that R is ₄ And R ₅ At least one of them represents unsaturated C ₁₁ -C ₂₉ An alkyl group.

15. The pharmaceutical preparation according to claim 14, wherein the pharmaceutical preparation comprises at least one radical inhibitor (c) of the general formula (II), wherein the group R ₄ And/or R ₅ Is at least monounsaturated C ₁₅ -C ₂₁ Alkyl, particularly preferably at least diunsaturated C ₁₅ -C ₂₁ Alkyl and very particularly preferably at least tri-unsaturated C ₁₅ -C ₂₁ An alkyl group.

16. The medicament according to any one of claims 1 to 15, characterized in that it comprises at least one free radical inhibitor (C) selected from vitamin F, vitamin E, vitamin C, vitamin a, vitamin B and vitamin H.

17. The medicament according to any one of claims 1 to 16, characterized in that it comprises one or more free radical inhibitors (c) in a total amount of 0.01 to 10.0 wt. -%, preferably 0.25 to 7.0 wt. -%, more preferably 0.25 to 6.0 wt. -% and most preferably 0.25 to 2.5 wt. -%, based on the total weight of the medicament.

18. The agent according to any one of claims 1 to 17, characterized in that it comprises at least one basifying agent.

19. A process for lightening keratin fibres, characterized in that at least two formulations (A) and (B) packaged separately from one another are mixed to form an application mixture which is applied to the fibres and rinsed off again after a contact time, wherein

-the formulation (a) comprises hydrogen peroxide (a 1), and

-said formulation (B) comprises

-at least one complexing agent (b) of general formula (I) as defined in claims 1 to 17 and

-at least one radical inhibitor (c) as defined in claims 1 to 17.

20. A process for lightening keratin fibres, characterized in that at least three formulations (A), (B) and (C) packaged separately from one another are mixed to form an application mixture, which is applied to the fibres and rinsed off again after a contact time, wherein

-the formulation (a) comprises hydrogen peroxide (a 1), and

-the formulation (B) comprises at least one persulfate (a 2) selected from ammonium, potassium and sodium peroxodisulfate, and

-said formulation (C) comprising at least one complexing agent (b) of general formula (I) as defined in claims 1 to 17 and

-comprising at least one radical inhibitor (c) as defined in claims 1 to 17.